The final goal of the research is to understand the origin and racial lineage of the Japanese through clarifying the features of oral cavity of natives in various regions of Japan and neibouring countries. This study describes the dental arch and the palatal traits in Taiwanese males. Ninety-six Taiwanese males, 18 to 24 years old, and 214 Japanese males, as a control, had impressions taken and plaster models made. The measurements were made on the models. The data of Taiwanese males were also compared with those of Taiwanese females, Taiwan aborigonal males, Japanese males (Okinawa and Ishigaki Island), Korean males and Mongolian males. The length and breadth of dental arch, and posterior palatal height in Taiwan males were greater than those in Taiwan females. Dental arch lengths tended to be shorter but dental arch breadths tended to be greater in Taiwanese males than in Japanese males (Okinawa and Ishigaki Island). Dental arch lengths tended to be longer, palatal breadths and lower alveolar breadths in anterior region tended to be greater but those breadth measurements in posterior tended to be smaller in Taiwanese males than in Taiwan aboriginal males. Posterior dental arch length was similar but dental arch breadth tended to be greater in Taiwanese males than in Korean males. Dental arch breadths were similar but dental arch lengths tended to be longer in Taiwanese males than in Mongolian males. The height of the palate tended to be smaller in Taiwanese males than in Japanese males and Taiwan aboriginal males. These findings were similar to the results of studying oral traits in Taiwanese females when compared with other races, and indicated that the morphology of the dental arch and palate in Taiwanese males differed from that of Japanese and Taiwan aboriginal males.

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With use of 33 mongrel adult dogs, the inferior alveolar nerves in the mandibular bone defect made and covered with a silicon sheet were resected experimentally, and the group with the inferior alveolar arteries and veins resected and the group with those retained were compared histopathologically. Granulation in the bone defect started from three days after operation in both the vas-resected group and vas-retained group. All blood clots were replaced by granulation tissue in 30 days in the vas-resected group and in 21 days in the vas-retained group. Neogenesis of bone was seen from five days after operation in both groups. Although the amount of new bone was slightly greater in the vas-retained group, continuation of new bone was not seen in either group even 90 days after operation. The cause of this was attributed to the blocking-off of the periosteum by the silicon sheet. In the vas-resected group, no neogenesis of vessels was seen from the trunk of the inferior alveolar artery which was resected with the artery ligated, and neogenesis of vessels was thought to be from the resected ends of branches of the inferior alveolar artery. Retrograde degeneration of nerve fibers was seen from one day after operation in both groups. No marked differences in the extent and time of degeneration were seen between the two groups and the course of degeneration was similar to those reported previously. Wallerian degeneration of nerve fibers was seen from one day after operation and reached a peak from five to seven days after operation, and the degenerated nerve fibers about disappeared 21 days after operation. Around the degenerated nerve fibers, macrophage-like cells were observed and these cells were thought to be involved in phagocytosis. Proliferation of Schwann cells was seen from five days after operation in both groups and the direction of proliferation of Schwann cells was more linear in the vas-retained group than in the vas-resected group. Extension of regenerated nerve fibers was seen from seven days after operation, following the proliferation of Schwann cells, and the resected ends were connected in 30 days after operation. The direction of regeneration of nerve fibers was more linear and the number of nerve fibers reaching peripheries was greater, and thicker fibers were found more in the vas-retained group than in the vas-resected group. On the basis of the foregoing findings, importance of the role played by the blood vessels accompanying regeneration of nerves was indicated.

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The purpose of this study was to investigate the root formation of the tooth affected by orthodontic movement of the adjacent tooth. Thirty rabbits from ten to twelve weeks old were investigated histopathologically. Orthodontic elastic chain was used for the tooth movement, and the lower right 1st premolar was moved mesially with the anchorage of the left lower incisor. On setting the elastic chain, the crown of the lower right 2nd premolar was cut. Thirty rabbits were divided into two control groups (non-treated group and the 2nd premolar cut group) and two experimental groups (initial load approximately 50g and 200g groups). Each group had three rabbits. The experimental groups were investigated at the 2nd, 4th, 6th and 8th week after appliance setting during the experiment. Upon completion of the experiment, the changes occurring in the lower right premolars and molars and in the periodontal tissues were investigated histopathologically and compared with those of control groups. The results were as follows : 1. Physiologically, on the mesio-distal tooth movement in the control groups, the lower right 1st premolar moved mesially. The 2nd molar did not move mesio-distally and the lower molars moved distally. 2. As a result of applying force in the mesial direction to the crown of the lower right 1st premolar, the tooth moved and inclined mesially beyond the physiological limit. 3. In the 50g group, the lower right 2nd premolar and some of the 1st molar moved mesially and curved at the 4th week and thereafter after laoding. 4. In the 200g group, mesial movement and curvature of the lower right 2nd premolar occurred from the 2nd week after loading. Such changes in the 1st molar was observed at the 4th week after loading. At the 6th and the 8th week, neither mesial movement nor physiological distal movement of the 1st molar was observed. The above results histopathologically substantiate that an orthodontic tooth movement affects the development of the basal portion of the adjacent tooth. The results also suggest that clinical orthodontic tooth movement should be done with care in mixed dentition where many incompleted teeth exist.

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Chemotherapy for oral cancer, used alone or in combination with surgical therapy and radiation therapy appropriately, is no doubt a very important treatment method for prevention of local recurrence and distal metastasis, etc. Although many anticancer agents used today clinically have rather strong side effects, their administration for an extended period and in a large quantity is desirable from the standpoint of treatment. In anticipation of minimizing side effects and increasing anticancer effects, attempts are made to combine non-anticancer agents clinicaly such as vitamins and alkaloid. Of these non-anticancer agents, vitamin C (VC) is one of agents expected to restrain proliferation of tumors and to have immunological effect. It is used in combined administration with an anticancer agent and reported to increase anti-tumor effect clinically. Although the combined use of VC increases anti-cancer effect, cytocidal effect on normal cells and tissues also is expected from its use. It is therefore necessary to determine its cytocidal effect on the tissue of the oral cavity. The effect of the combined use of VC with Bleomycin (BLM) and Mitomycin C (MMC), most frequently used chemotherapeutic agents for oral cancer, on the submandibular gland of domestic rabbits was investigated histopathologically from the view point of side effects in the oral cavity region. The results were as follows : 1. The dosage of VC which did not affect the submandibular gland was 60 mg/kg/day. This dosage of VC was used in the combined administration of BLM and MMC thereafter. The dosage of anticancer agents were BLM (2.5mg/kg/day) and MMC (0.3mg/kg/day). 2. At the terminal portion of the submandibular gland, BLM-VC and MMC-VC combined administration cases, as compared with independent administration cases of BLM and MMC, showed marked findings such as atrophy of cytoplasm, pyknosis and deformation of nucleus, and even destruction of acinous cells (A and B cells). Along with these regressive changes, considerable decrease was observed in fine granules of A cells, PAS positive substance, and A・M stainable substance. 3. At the epithelial cells of duct constituting the intercalated duct and striated duct, both BLM-VC and MMC-VC administration cases, as compared with independent administration cases of BLM and MMC, markedly showed regressive changes such as atrophy of cytoplasm, pyknosis and deformation of nucleus. The surrounding capillary vessels showed stagnation, hyperemia, and dilation. 4. At the excretory duct in BLM-VC and MMC-VC combined administration cases, as compared with that in independent administration cases of BLM and MMC, the regressive changes in cytoplasm and nucleus of the epithelial cells were slight. 5. The foregoing regressive changes in acinous cells and epithelial cells appeared first in the peripheral part of the gland, gradually extended to the mid-gland, and intensi-fied. In the 15-dose cases, regressive changes were observed markedly in the whole gland. 6. The agents BLM and MMC both showed more marked regressive changes as their effects of combined use with VC than their independent administration. However, no apparent histologic changes specific to each agent were found. 7. On the basis of the foregoing experimental results, BLM and MMC not only showed morphological changes but also affected functions such as synthesis, accumulation, and excretion of secretory substances. The combined use of VC was though to aid and promote these regressive changes and reduction in functions further.

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Orthopantomography is being increasingly used not only for radiographic examination of the edentulous jaws, but also for the examination of the alveolar region in dental implants or denture construction. It is essential that dentists know the magnification factor of the alveolar region when orthopantomography is utilized for comprehension of alveolar bone content. In this study, therefore, the vertical magnification factor of the alveolar region at different jaw positions in orthopantomography was obtained experimentally. The results were as follows : 1. The test piece used in this experiment had a bucco-lingual width of 14 mm at the [numerical formula] region, 12 mm at the [numerical formula] region, and 10 mm at the [numerical formula] region. The difference in the vertical magnification factor of the buccal and lingual regions usually varies in proportion to the width between them. But, when the jaws are kept in the standard position and their occlusal plane is horizontal, the vertical magnification factor of the [numerical formula] region is larger than that of the [numerical formula] region. Therefore, the bucco-lingual width and the difference of the vertical magnification factor do not always correspond to each other. 2. When the jaws are kept in the standard position and their occlusal plane is horizontal, the difference in the calculated vertical magnification factor at the middle of the alveolar region is not so different in the upper and lower jaws, nor in the individual regions. The maximum vertical magnification factor in the upper jaw is 1.23 of the <7|>___- region and the minimum factor is 1.22 of the <3|>___- region. Also the maximum vertical magnification factor in the lower jaw is 1.23 of the <7|>^^^- region and the minimum factor is 1.20 of the <4|>^^^- region. 3. The vertical magnification factor in the bucco-lingual portion of the alveolar region does not correspond to the estimated factor while the jaws are kept in the standard position while their occlusal plane is moved upward. Theoretically, the vertical magnification factor of the lingual portion should be larger than that of the buccal portion, but estimated factors were not always obtained. In this experiment the vertical magnification factor of the middle of the alveolar region did not change mathematically when the occlusal plane was moved upward. 4. The vertical magnification factor of the middle of the upper alveolar region is smaller than that of the lower alveolar region while the jaws are kept in the standard position and their occlusal plane is moved downward. The vertical magnification factor changes gradually to a smaller one moving to the <4|>___- region from the <7|>___- region. The vertical magnification factor of the lower jaw also changes gradually to a smaller one moving to the <4|>^^^- region from <7|>^^^- region as in the upper jaw. 5. The vertical magnification factor of the middle of the alveolar region, while the jaws are kept anteriorlly 10 mm from the standard position and their occlusal plane is horizontal, is smaller than that of the jaws kept in the standard position and kept posteriorlly 10 mm from the standard position. 6. Because the x-ray beam in orthopantomography is projected upward to the jaws, it makes a different vertical magnification factor in the upper and lower alveolar region. The antero-posterior position of the jaws and the vertical angulation of the occlusal plane are very influential in changing the vertical magnification factor. Then, it is essential to keep the jaws in the standard position and their occlusl plane horizontal when the orthopantomography is applied for the survey of the vertical alveolar bone content. However, it is more important to keep the horizontal occlusal plane than to keep the jaws in the standard position.

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Composite resins have been preferably used as the esthetic restorations. However, they sometimes produce certain pulpal irritation. It may be partly attributed to the presence of irritants involving unreacted substances such as residual monomers in the resin restoration. In this study, therefore, the permeability of those substances through dentin structure into pulpal chamber was investigated using sound extracted teeth. The high speed liquid chromatography revealed that Bis-GMA and Tri-EDMA monomers and a substance having a molecular weight of about 140 were eluted in distilled water from the composite resin used. These residual substances could easily pass through the dentin when the resin was placed in the prepared cavity without removing the smear layer. There could be found no significant increase in the permeability by the acid treatment of the dentinal wall although it has been considered so far that the treatment would result in the increased permeability. When a light-chemical-curing bonding agent was applied to the acid-etched dentin, the penetration of Tri-EDMA was markedly decreased and that of the unidentified substance was entirely inhibited. A chemical-curing bonding agent, on the other hand, showed no significant effects on the permeability. Furthermore, the 3%FeCl_3 treatment of the dentin prior to applying the bonding agent showed much better ability to block the penetration of these substances, permitting only a small amount of Tri-EDMA to pass. It was found from SEM observations that the composite resins exhibited fairy tight bonding to the dentinal wall with the aid of the light-chemical-curing bonding agent while the chemical-curing bonding agent produced large interfacial gaps between them. No gaps were observed in the combined use of the light-chemical-curing bonding agent and chemical-curing composite resin on the 3%FeCl_3-pretreated dentin. Thus the permeability of the residual substances through dentin was well correlated with the presence of the interfacial gaps between the composite resin and dentinal wall. In addition, it was also suggested that the deposits resulting from 3%FeCl_3 treatment might play an important role to block the permeation of the residual substances by sealing the dentin tubules.

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The present study was undertaken to investigate the fine structure of salivary calculus. Fifteen cases of salivary calculus developing in the human submandibular gland duct were examined on the scanning and the transmission electron microscope (SEM and TEM) and an X-ray microanalyzer (EDX). The results were as follows : 1. The structure of salivary calculus was composed of alternate layers of a homogeneous and compact structure and a globular structure. The whole structure contained the core of salivary calculus in the center. 2. The layer of the homogeneous and compact structure showed marked calcification. It showed a tendency toward greater calcification than the layer of the globular structure. 3. Two types of microbe-like structure, rod-shaped and globe-shaped, were found in salivary calculus. These structures were presumed to be microorganisms because of their double membranes and nucleoid found in the TEM study. 4. The microorganism showing intramicroorganism calcification was presumed to be Bacterionema matruchotii from its form and ability for intra-and extra-microorganism calcification. 5. Although the crystals showing initial calcification in the low region of the low electron density presented various structural forms depending on different conditions, no microorganism was apparently involved in such calcification. 6. The main constituents of inorganic matters in salivary calculus were mainly Ca and P, and those of organic matters were K, Mg, Fe, Cr, Cl and Co.

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The inferior border of the mandible of ninety rats was frozen for three minutes with the rats grouped into freezing temperatures of -196℃, -100℃, and -25℃, and the histologic changes caused by freezing in the mandible and its related tissues were investigated histopathologically. The results are as follows : 1. Three days after freezing, the mandible showed hypochromatosis, and degeneration and disappearance of osteocytes. The extent of the changes was to the molar region of the alveolar bone in the -196℃ group, to the inferior border of the mandibular canal in the -100℃ group, and limited to the compact bone in the inferior border of the mandible in the -25℃ group. 2. Three days after freezing, osteoclasts appeared in part of the border in the -196℃ and -100℃ groups. On the fifth day, bone resorption and bone generation started in part. After two weeks, resorption and apposition of bone were observed extensively. At the sixth week, bone with osteocytes missing was found still remaining. 3. The medullary cavity showed bone formation in these two groups from the fifth day after freezing and marked networks of bone formation on the seventh day. It was filled with new trabeculae at the second week. 4. In the dental pulp of the incisor, degeneration and disappearance in part were seen in the pulp cell and odontoblasts three days after freezing. On the fifth day, hyaline degeneration was seen in the whole dental pulp at the frozen site. After two weeks, various cells began to be restored gradually and new dentin formation started. Periodontal ligament of the incisor showed plasmotomy and disappearance in part in an early stage of the experiment. In the next stage, direct bone fusion with the inner wall of the alveolar bone and stoppage of eruption were seen. 5. In the inferior alveolar nerve three days after freezing, hypochromatosis, swelling, plasmotomy, and granular degeneration were observerd in most nerve fibers in the -196℃ group and in part of the nerve fibers in the -100℃ group. In the -25℃ group, almost no changes were seen. 6. Seven days after freezing, the -196℃ and -100℃ groups showed minute nerve fibers crossing each other and extending among Schwann cells in the degenerated inferior alveolar nerve. After two weeks, the minute fibers extended to the peripheries beyond the frozen site, and increased in the number of fibers, in descending order of the -196℃, -100℃, and -25℃ groups. 7. After six weeks, the number of the regenerated nerve fibers distributed in the inferior alveolar nerve and incisal periodontal membrane approximated the normal in the -196℃ and -100℃ groups. 8. When the inferior border was frozen for three minutes at -196℃, -100℃, and -25℃, the temperatures in the mandibular canal were -22℃, -7℃ and 18℃, respectively. On the basis of the foregoing findings, nerve tissue was affected not only by the effect of freezing but also by the surrounding soft tissue. In the cases where bone tissue surrounds the nerve, regeneration of the nerve was found to be slightly delayed. In view of this, in performing cryosurgery, anatomical structure, freezing direction, and temperatures must be duely taken into consideration.

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The growth change of the head and face in Kamigoto students and methods used in the study of growth data were studied. Furthermore, period and local variations were examined. The results were as follows : 1. Methods used in the study of growth The cross-sectional method with reliable data was considered to result in more exact estimation of mean and increment than the longitudinal or the mixed longitudinal method. 2. Change of stature with growth Adolescent growth spurt was found in male from 11 to 13 years old and in female from 9 to 11 years old. This spurt continued for 3 years, and the occurrence in female was 2 years earlier than in male. Childhood growth spurt was found in male from 7 to 8 and from 9 to 10 years old, and in female from 7 to 8 years old. Moreover, the increment at this time showed an increasing tendency. The growth pattern of Kamigoto students was about the same as the standard growth pattern of Japanese. 3. Change of the head and face with growth a. Change of the measurement Adolescent maximum spurt of the head and face was correlated with that of the stature at adolescent growth spurt. Moreover, childhood growth spurt also showed close correlation. b. Change of the index The head shape tended to be dolichocephalic, hypsicephalic and acrocephalic, and the face shape tended to be leptoprosopic. These changes were influenced by increment of the head length, the morphological facial height and the head height. 4. Sex difference with growth The sex difference in adult of the stature and the head and face was influenced greatly by adolescent maximum spurt in male. After this spurt occurred, sex difference was obviously shown. 5. Comparison a. Period variation with growth Brachycephalic tendency occurring by period was influenced by increment of the head breadth. The secular change in growth showed a tendency toward taller stature and prematurity. b. Local variation with growth No distinct difference was found in the comparison of the head length, the head breadth and the stature of Kamigoto students with those of Okinawa, Osaka, and Tokyo students. This finding indicated reduction in local variations.

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Pulpotomy at the middle portion of the root canal was performed on immature teeth of young adult dogs. Healing process of the pulpal wounds, change in nerve fibers in the dental pulp, process of the formation of the dentin barrier, and apical closure including growth of the root were investigated under the light and the electron microscope. The results were as follows : 1. Three days after operation, a necrotic layer was formed extensively directly under the pulpotomied surface, and the nerve fibers in the inflammatory layer directly under the necrotic layer were degenerated. Observation under thc transmission electron microscope (TEM) of this region showed undifferentiated mesenchymal cells poor in cell organellae and nerve fibers with marked destruction of myelin of the myelin sheath. At the root apex, Hertwig's epithelial sheath was observed. 2. A week after operation, a calcified barrier was beginning to be formed on the pulpotomied surface and slight inflammatory cellular infiltration limited to the dental pulp directly under the surface was seen. Directly under the barrier, cells which were comparatively large in cell and nucleus sizes were found. The TEM observation of these cells showed cells which had nuclei with small depressions in part, were rich in rough-surfaced endoplasmic reticula, and showed wide intercellular space. 3. At the second week after operation, the formation of the dentin barrier was beginning to be seen directly under the pulpotomied surface. Observation of this region, viewed from the pulpal side, under the scanning electron microscope (SEM) showed large and small calcospherite-like structures fused together and piled. The TEM observation of the cells at this region showed large oval nuclei with gently sloped depressions, and many rough-surfaced endoplasmic reticula and mitochondria in cytoplasm around the nucleus, and odontoblast-like cells connected by junctional complex. The TEM observation of the nerve fibers showed normal nerve fibers of laminated structure with orderly formed myelin sheath. At the root apex from this time, addition of connecting cellular cementum was seen and the TEM observation showed active cementoblasts in both the control and experimental groups. 4. The cases from one to two months after operation showed the formation of the dentin barrier with dentinal tubules, on the pulpotomied surface, continuously from the periphery to the center of the pulp. The SEM observation of this region showed peritubular dentin on the coronal side, but its borders with matrix were distinct at some places and indistinct at other places. Dentinal tubules were not uniform. The TEM observation of the cells directly under the barrier showed, as in the case of odontoblasts of root dentin, large ovoid nuclei poor in chromatin, and uneven distribution of cell organellae such as mitochondria and many rough-surfaced endoplasmic reticula. As to the nerve fibers in the dental pulp, small nerve bundles and single nerve fibers were ascending toward the dentin barrier. Active apposition of cellular cementum was seen at the root apex and the TEM observation of this region showed cells with a large oval nucleus and rich in rough-surfaced endoplasmic reticula and mitochondria. 5. Six months after operation, the dentin barrier was thickened. The SEM observation of the dentin barrier showed that, on the pulpal side, calcospherites were orderly distributed, fused and increased in compactness, and had uniform dentinal tubules. The nerve fibers, at this time, reached near the dentin barrier with some running parrarel with the dentin barrier and terminating in the odontoblast layer and some infiltrating into the barrier together pulpal intrinsic tissue and blood vessels. At the root apex, slight internal resorption of dentin was observed in part and the formation of cementum with inclusion of cementocytes was seen in those sites. Calcification was completed

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Three-week-old male rats of Wistar strain were given a calcium-deficient diet and experimental osteoporosis was induced in them. They then were given 1α-OH-D_3 (0.05μg/kg, 3 times/week and 0.1μg/kg, 3 times/week) and its effect on the mandibular condyle and proximal epiphysis of the tibia was investigated radiologically, histopathologically and electronmicroscopically. The results were as follows : I. Radiological findings 1. In the mandibular condyle and proximal metaphysis of tibia, dense osseous layers were more distinct and trabeculae were running more compactly and their widths were narrower in the 0.05D_3 and 0.1D_3 groups than in the calcium-deficient diet group. 2. The tibia epiphysis was formed better in the 0.1D_3 group than in the calciumdeficient diet group or in the 0.05D_3 group. Dense osseous layers were seen in part and trabeculae were increased but were running with their widths narrower. II. Histopathological findings 1. Contact microradiogram findings In the mandibular condyle, tibia epiphysis and tibia metaphysis, the granular trabeculae of primary spongiosa were greater in number and the trabeculae of secondary spongiosa were running with their widths narrower in the 0.05D_3 and 0.1D_3 groups than in the calcium-deficient diet group. 2. General tissue findings i. The cartilage layer in the mandibular condyle and in the tibia epiphysis was thinner due to decrease in proliferative chondrocytes and hypertrophic chondrocytes in the 0.05D_3 and 0.1D_3 groups than in the calcium-deficient diet group. Many findings of erosion of calcified matrix by chondroclasts were seen and subchondrocyte bone formation was increased. Trabeculae however were thinner due to the appearance of osteoclasts. ii. The cartilage layer in the tibia metaphysis was thinner due to decrease in hypertrophic chondrocytes in the 0.05D_3 and 0.1D_3 groups than in the calcium-deficient diet group. Findings of erosion of calcified matrix by chondroclasts were increased and intrachondrocyte bone formation was also increased. Trabeculae however were thinner due to the appearance of osteoclasts. III. Electron microscope findings 1. Scanning electron microscope findings In the three groups, longitudinal matrix in cartilage lacunae of the mandibular condyle were incomplete in many places and collagenous fibrils were not calcified in places. The walls of cartilage lacunae in the areas of subchondrocyte bone formation were composed of incomplete longitudinal matrix. In the base of bone lacunae, large and small openings of bone canalicules were seen clearly. In the calcium-deficient diet group, the areas of subchondrocyte bone formation showed irregular and fewer trabeculae. 2. Transmission electron microscope findings No ultramicrostructual differences in osteoclasts were found in the three groups. In each group, ruffled borders were developed and bone resorption was active. Osteoblasts showed more developed cristae of mitochondria and more cytoplasmic projections in the 0.05D_3 and 0.1D_3 groups than in the calcium-deficient diet group. Collagenous fibrils were seen around the osteoblasts and active bone formation was seen. On the basis of the foregoing findings, dependency on the amount of administration of 1α-OH-D_3 to infirm bone tissue was seen in the mandibular condyle, tibia epiphysis and tibia metaphysis. Growth of cartilage cells was observed and bone formation was the highest in the mandibular condyle with tibia epiphysis and tibia metaphysis following.

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It is difficult to identify the race between Japanese and Taiwanese because Taiwanese are thought to be one of the origins of Japanese. The purpose of this study was to investigate the racial differences of the facial morphology between Japanese and Taiwanese females. Material consisted of 104 standardized Moire photographs. Fifty-three were of Japanese females and 51 of Taiwanese females. The width and the height of each facial part were measured. Forty-four measurements obtained from each standardized Moire photograph were used to evaluate the interracial differences by multivariate analyses. The results were as follows : 1) R-mode cluster analysis and principal component analysis were applied to the data to make clear the correlations between 44 variables. Ten clusters were constructed at the level of seventy-five similarities in R-mode cluster analysis and eight factors were obtained in principal component analysis. 2) The data were subjected to a stepwise discriminant function analysis using the original 44 variables. Six variables (X5, X6, Z1, Y3, Y28, Z7) were selected as the best discriminators. The incidence of correctly classified cases was 95.19%. 3) The selected variables showed significant differences at the level of 0.1% in Student's t-test. X5, X6 and Z1 in Taiwanese females were larger than ones in Japanese females. On the other hand Y3, Y28 and Z7 in Japanese females were larger than ones in Taiwanese females. 4) Fourier coefficients were caluculated from each cross section at the level of the buccal, nose, and lower lip and the sagittal section at the midline. The comparison of the mean patterns between Japanese and Taiwanese females supported the results of the linear measurements.

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The authors had made a histological and histochemical investigation on the polysaccharides in the von Ebner's glands of the Afghan pika, Ochotona rufescens rufescens. The results were as follows : 1. The acini of the von Ebner's gland in the pika were similar to those reported for the exocrine serous glands. An oval nucleus and flattened rough endoplasmic reticulum cisternae were located densely in the basal half of cell. The apical portion of the acinar cell was filled with homogeneous secretory granules. 2. The granules were observed to have a distinct limiting membrane and homogeneous contents. These were poor in mucosubstance (weakly positive to PA-TCH-SP staining). The duct cells contained secretory granules which contained a dense core within a lighter matrix and were intensely positive to PA-TCH-SP staining. 3. The acinar cells showed weak reactions to sialomucin and neutral mucopolysaccharide, but the reaction to sulfomucin was unrecognizable. 4. Several mucous cells were found among the von Ebner's glands. 5. The von Ebner's glands of the Pika had mucous substances. Therefore, these glands are the seromucous glands.

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Extracted maxillary and mandibular molars with the curved fine root canals untreated were employed. Enlarging and preparation of the root canals were made with ultrasonic files during the root canals were poured water. Two cleansers, NaOCl (1.25%, 2.5%, 5%) and EDTA (1.875%, 3.75%, 7.5%), were used in combination for ultrasonic cleansing and the inner walls of the root canals were observed by SEM. The results were as follows : 1. When the canals were cleansed with water only, smeared layer was observed in mid-canal and root apex ; the root canal could not be cleansed sufficiently. 2. When the canals were cleansed with 1.25% NaOCl-1.875% EDTA and 2.5% NaOCl-3.75% EDTA, cleansing effects were sufficient at mid-canal but insufficient at root apex. No difference was found between the two. 3. When the canals were cleansed with 5.0% NaOCl-7.5% EDTA, cleansing effect was sufficient at mid-canal and root apex.

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Phosphate-bonded investments exhibit exothermic reaction during setting. The generating heat may cause expansion and/or deformation of the wax pattern embedded in the investment. In this study, the temperature change in the investment mold during setting was measured for five commercially available phosphate-bonded investments. The temperature of the investment mold began to rise a few minute after the start of mixing. The temperature curve was significantly dependent on material, ring size and mixing method. A temperature peak appeared at about 10 to 30 min. In general, the shorter the peak time, the higher the peak temperature ranging from about 35 to 80℃. They were primarily affected by the materials used. The peak temperature was increased with increase in the ring size while no consistent tendencies were found in the effects of the mixing method.

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A total of 68 cases diagnosed as epulis in the Second Department of Oral Surgery, Kyushu Dental College Hospital, during the period from 1969 to 1988, was clinically analysed. The results were as follows : 1. A series of 68 cases of epulis has been treated by conservative surgical excision. This series was classified histopathologically to be ; 27 cases epulis granulomatosa (39.7%), 13 cases epulis fibrosa (19.1%), 12 cases epulis hemangiomatosa (17.6%), 10 cases epulis fibromatosa (14.7%), 4 cases epulis osteoplastica (5.9%), 1 case giant cell epulis (1.5%) and 1 case congenital epulis (1.5%), according to Ishikawa classification (1982). 2. The majority of 68 epulis cases was in patients between 40 to 50 years of age. By sex, the incidence was 2.4 times greater in females than in males. 3. These lesions were located more frequently on the maxillary gingiva (60.3%) than on the mandibular gingiva (39.7%). The epulis in the majority of 68 cases was located in the anterior segments of the jaws. 4. The epulis in the majority of 68 cases was smaller than the thumb tip. 5. As to the recorded known duration, the incidence under 1 year was 60.3% and over 2 years was 25%. 6. In 20 cases (29.4%), the chronic local irritations were considered as the cause of these lesions. 7. Treatment was performed all by surgical excision. In 26 cases (38.2%), extraction of the adjoining teeth was performed. The prognosis is good and no recurrence is noticed in any case.

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A total of 32 cases of oral cancer in patients over 70 years old treated in our clinic, during 1977 to 1986, was clinical analysed. The following results were obtained : 1) A series of 32 primary cases with oral cancer in the elderly patients over 70 years old was reported. The ratio of the elderly patients over 70 years of age was 25.2% (32/127 cases). As to sex, incidence was higher in males. 2) The oral cancer in patients over 70 years old in the majority of 32 cases was located on the upper or lower gingiva (65.6%). 3) This series was found histopathologically to be ; 23 cases squamous cell carcinoma (71.9%), 5 cases undifferentiated carcinoma (15.6%), 2 cases verrucous carcinoma (6.3%), 1 case adenoid cystic carcinoma (3.1%), 1 case malignant melanoma (3.1%). 4) In TNM classification, the majority of 32 cases were T_2, T_3 case and Stage III case. 5) The ratio of the complications was 53.1% (17/32 cases). 6) Treatment was performed mostly by combination chemotherapy with provisional operation and/or radiation therapy. 7) The five year absolute cure rate for 32 cases was 26.4%.

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